A hybrid automatic repeat request (HARQ) operation can be applied as a method for controlling data reception failure. When a data transmitter receives an ACK signal from a data receiver after transmitting a packet to the data receiver, the data transmitter can transmit a new packet. If the data transmitter receives a NACK signal from the data receiver, the data transmitter can retransmit the previously transmitted packet. In this case, a packet to which encoding according to forward error correction (FEC) has been applied can be retransmitted. Accordingly, the data receiver decodes a received packet and transmits an ACK signal upon successfully decoding the received packet. When the data receiver does not successfully decode the received packet, the data receiver transmits a NACK signal and stores the received packet in a buffer. Upon reception of a retransmitted packet according to the NACK signal, the data receiver combines the retransmitted packet with the packet stored in the buffer and decodes the combined packet to improve packet reception success rate.
A conventional wireless communication system has defined 8 independent HARQ processes for each cell. A buffer is allocated to each HARQ process. In addition, if multiple cells are configured for each user equipment (UE), 8 independent HARQ processes are configured per cell. Accordingly, assuming that N cells are configured, (8*N) HARQ processes should be configured. In addition, a buffer is configured per HARQ process. In this case, since total memory capacity of the UE is limited, memory capacity capable of being allocated to one buffer is gradually reduced as the number of configured HARQ processes and buffers increases.